郯庐断裂带的平移运动与成因

Transcurrent movement and genesis of the Tan-Lu fault zone

在华北、华南板块碰撞期间,郯庐断裂带究竟是何种边界仍是没有解决的重大地学问题,许多学者对此提出了不同的构造解释模式。关于郯庐断裂的平移距离仍存在着较大的分歧与有待深入研究之处。在华北、华南板块拼合之后,郯庐断裂带发生了一次大规模的左行平移,其糜棱岩的40Ar/39Ar年龄为132～119Ma,指示为早白垩世的平移活动,平移活动中伴生了强烈的岩浆活动。这期左行平移标志着中国东部构造的重大转折,是滨太平洋构造对前期古特提斯构造的叠加,其动力学机制为太平洋区伊佐奈岐板块突然出现的高速斜向俯冲。

It is still an outstanding major scientific issue what type of boundary the Tan-Lu fault was dur-ing collision of the North and South China plates.Different interpretative tectonic models have been pro-posed.Divergent views exist as to the magnitude of displacement of the fault zone and more studies are needed.The fault zone experienced a large-scale left-lateral displacement after the collage of the North and South China plates. 40 Ar / 39 Ar ages of relative mylonites range from132to119Ma ,indicating Early Creta-ceous wrench faulting.The Early Cretaceous wrench faulting was accompanied by intense magmatism.The left-lateral displacement of the Tan-Lu fault zone in the Early Cretaceous marks very important tectonic turning in eastern China,which shows overprinting of circum-Pacific tectonics on pre-existing Tethys tec-tonics.Its dynamic mechanism is the sudden onset of high-speed oblique subduction of the Izanagi plate in the Pacific region.